A 6-ounce box of strawberry gelatin costs $0.90 and a 3-ounce box costs $0.42.

What is the difference in cost per ounce between the larger and the smaller boxes?

To find the cost per ounce for each box, we divide the total cost by the number of ounces.

Cost per ounce for the 6-ounce box:
$0.90 / 6 oz = $0.15/oz

Cost per ounce for the 3-ounce box:
$0.42 / 3 oz = $0.14/oz

The difference in cost per ounce between the larger and smaller boxes is:
$0.15/oz - $0.14/oz = $0.01/oz

Therefore, the difference in cost per ounce between the larger and smaller boxes is $0.01.